Timber is a commonly utilized material in building construction, and is often used in load bearing applications. The refined microstructure of wood provides a low weight but excellent load bearing capacity. Despite its low weight, wood has a strength 14 times that of steel.
For load bearing uses in construction, wood is chosen for a given application according to a minimum modulus of elasticity (MOE) which is a measure of stiffness, and in turn strength of a beam. The MOE for a timber varies according a number of factors, however the main factor being the wood species. The load bearing capacity of a timber beam is a function of the physical dimensions of the beam, as well as the MOE. Beams of high cross-sectional area sawn from hardwood species are typically chosen to high load bearing applications.
Timber beams capable of bearing significant load are expensive. For reasons of economy, the prior art provides many techniques by which wood members may be laminated together to provide a composite timber joist. Techniques for end-joining to provide timber joists of the required span are also known. Such techniques allow for the use of timbers having smaller-cross sectional areas, and shorter spans (such as “peeler cores”) to be used in constructing higher value structural beams. Some problems in these prior art approaches derive from the need to both laminate timber together to increase cross-sectional area and also incorporate means for joining timbers end-to-end. End-joining techniques using dowels are typically used, however careful placement of dowels is required so as so not interfere with the lamination means used. Even where care is taken, the combination of lamination and end-joining can lead to areas or points of potential failure.
It is an aspect of the present invention to ameliorate or overcome a problem of the prior art by providing improved means for laminating and end-joining timbers to provide high value timber timber joists. It is a further aspect to provide an alternative to prior art means.
The discussion of documents, acts, materials, devices, articles and the like is included in this specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.